@article{Welch2017,
title = {Dietary Magnesium May Be Protective for Aging of Bone and Skeletal Muscle in Middle and Younger Older Age Men and Women: Cross-Sectional Findings from the UK Biobank Cohort.},
author = {AA Welch and J Skinner and M Hickson},
url = {https://www.ncbi.nlm.nih.gov/pubmed/29084183},
year = {2017},
date = {2017-10-30},
journal = {Nutrients},
abstract = {Although fragility fractures, osteoporosis, sarcopenia, and frailty are becoming more prevalent in our aging society the treatment options are limited and preventative strategies are needed. Despite magnesium being integral to bone and muscle physiology, the relationship between dietary magnesium and skeletal muscle and bone health has not been investigated concurrently to date. We analysed cross-sectional associations between dietary magnesium and skeletal muscle mass (as fat free mass-FFM), grip strength, and bone density (BMD) in 156,575 men and women aged 39-72 years from the UK Biobank cohort. FFM was measured with bioelectrical impedance and was expressed as the percentage of body weight (FFM%) or as divided by body mass index (FFMBMI). Adjusted mean grip strength, FFM%, FFMBMI, and BMD were calculated according to quintiles of dietary magnesium, while correcting for covariates. Significant inter-quintile differences across intakes of magnesium existed in men and women, respectively, of 1.1% and 2.4% for grip strength, 3.0% and 3.6% for FFM%, 5.1% and 5.5% for FFMBMI, and 2.9% and 0.9% for BMD. These associations are as great or greater than annual measured losses of these musculoskeletal outcomes, indicating potential clinical significance. Our study suggests that dietary magnesium may play a role in musculoskeletal health and has relevance for population prevention strategies for sarcopenia, osteoporosis, and fractures.},
keywords = {11058, diet, osteoporosis},
pubstate = {published},
tppubtype = {article}
}

Although fragility fractures, osteoporosis, sarcopenia, and frailty are becoming more prevalent in our aging society the treatment options are limited and preventative strategies are needed. Despite magnesium being integral to bone and muscle physiology, the relationship between dietary magnesium and skeletal muscle and bone health has not been investigated concurrently to date. We analysed cross-sectional associations between dietary magnesium and skeletal muscle mass (as fat free mass-FFM), grip strength, and bone density (BMD) in 156,575 men and women aged 39-72 years from the UK Biobank cohort. FFM was measured with bioelectrical impedance and was expressed as the percentage of body weight (FFM%) or as divided by body mass index (FFMBMI). Adjusted mean grip strength, FFM%, FFMBMI, and BMD were calculated according to quintiles of dietary magnesium, while correcting for covariates. Significant inter-quintile differences across intakes of magnesium existed in men and women, respectively, of 1.1% and 2.4% for grip strength, 3.0% and 3.6% for FFM%, 5.1% and 5.5% for FFMBMI, and 2.9% and 0.9% for BMD. These associations are as great or greater than annual measured losses of these musculoskeletal outcomes, indicating potential clinical significance. Our study suggests that dietary magnesium may play a role in musculoskeletal health and has relevance for population prevention strategies for sarcopenia, osteoporosis, and fractures.

@misc{Welch2016,
title = {Associations between dietary protein and magnesium and skeletal muscle mass and strength in men and women from the UK Biobank Cohort},
author = {Ailsa A Welch, Mary Hickson},
year = {2016},
date = {2016-04-22},
abstract = {Background
The maintenance of skeletal muscle mass and function is crucial in maintaining mobility and quality of life in our populations. The loss of skeletal muscle mass and function are risk factors for the onset of frailty and sarcopenia and mortality. Intake of dietary protein is important for prevention of the age-related loss of the skeletal muscle mass and function although intervention studies with dietary protein in people with sarcopenia have found inconsistent results (1,2). It is important to identify other potential nutrients for the treatment and prevention of sarcopenia and we recently found that magnesium intake was positively related to skeletal muscle mass and leg explosive power in a cross-sectional study in women of all ages (3). As magnesium is integral to skeletal muscle physiology and protein synthesis we therefore investigated the association between protein and magnesium intake and indices of skeletal muscle mass and strength in men and women from the UK Biobank Cohort. We investigated firstly the independent associations between protein and magnesium intake on the outcomes of skeletal muscle mass and grip strength and secondly the relationship between protein and magnesium intake on these outcomes.
Methods
We investigated the association between skeletal muscle mass measured as fat free mass (FFM) with Bioelectrical Impedance (Tanita BC-418 MA – Tanita Corporation, Arlington Heights, IL.), and hand grip strength (measured with the Jamar J00105 hydraulic hand dynamometer) and dietary intake of protein (as a percentage of energy) and magnesium measured using a 24-hour recall method in 12,602 men and women (5,678 men and 6,924 women) aged 40-69 years in the UK Biobank Study with complete data for all body composition and dietary measurements. For grip strength the maximum of both hand measurements was used. Total FFM was expressed either as the percentage of body weight ((FFM kg/body weight kg)*100) or the fat free mass index (FFMI – fat free mass in kg/height2). Dietary intake was divided into quintiles and regression analysis (analysis of covariance) was used to calculate the associations between the measures of body composition and grip strength and adjusted for the covariates of age, smoking status, physical activity, energy intake, dietary mis-reporting, and menopausal status and HRT medication in women. FFMI was also adjusted for total fat mass and grip strength for standing height. Analysis was performed in STATA SE 14.0.
Results
Mean age in men was 56.7 Y in men and 55.4 Y in women. Whole body mean FFM% was 76.1% and 65.3% and mean FFMI was 20.3 kg/m2 and 16.5 kg/m2 in men and women, respectively. FFM% was significantly and negatively associated with percentage protein intake (-0.33% per quintile (P trend <0.001) in men and -0.28% (P<0.001) in women) whereas for magnesium intake the association was positive (0.42% per quintile (P trend <0.001) in men and 0.45% per quintile in women (P<0.001)), in the fully adjusted models. With both nutrients together in the statistical models the association with protein was more negative and that of magnesium was more positive in men (protein -0.36% (P<0.001), magnesium 0.46% (P<0.001) and protein -0.32% (P<0.001), magnesium 0.50% (P<0.001) in women, indicating an interaction between the nutrients. There was no association between FFMI or grip strength and either dietary protein or magnesium in either men or women.
Conclusion
We found strong positive associations between magnesium intake and FFM% and a negative association with protein. The finding of the direction of the association with protein was surprising, although given the inconsistent results from previous cross-sectional and interventional studies may not be entirely unexpected. However, the associations were strengthened when both nutrients were included in the statistical model, suggesting an interaction and supporting our previous findings for magnesium that were previously found only in a female population (3). We also found no association between grip strength and either nutrient also supporting our previous findings (3). These results suggest the interaction between protein and magnesium intake on skeletal muscle mass and function deserves further research.
References: (1) Murton AJ, Proc Nut Soc, 74, 387-396 (2) Hickson M, Proc Nut Soc, 74, 378-386 (3) Welch AA et al, JBMR, 2015 Aug 19. doi: 10.1002/jbmr.2692.
This research has been conducted using the UK Biobank Resource

Background
The maintenance of skeletal muscle mass and function is crucial in maintaining mobility and quality of life in our populations. The loss of skeletal muscle mass and function are risk factors for the onset of frailty and sarcopenia and mortality. Intake of dietary protein is important for prevention of the age-related loss of the skeletal muscle mass and function although intervention studies with dietary protein in people with sarcopenia have found inconsistent results (1,2). It is important to identify other potential nutrients for the treatment and prevention of sarcopenia and we recently found that magnesium intake was positively related to skeletal muscle mass and leg explosive power in a cross-sectional study in women of all ages (3). As magnesium is integral to skeletal muscle physiology and protein synthesis we therefore investigated the association between protein and magnesium intake and indices of skeletal muscle mass and strength in men and women from the UK Biobank Cohort. We investigated firstly the independent associations between protein and magnesium intake on the outcomes of skeletal muscle mass and grip strength and secondly the relationship between protein and magnesium intake on these outcomes.
Methods
We investigated the association between skeletal muscle mass measured as fat free mass (FFM) with Bioelectrical Impedance (Tanita BC-418 MA – Tanita Corporation, Arlington Heights, IL.), and hand grip strength (measured with the Jamar J00105 hydraulic hand dynamometer) and dietary intake of protein (as a percentage of energy) and magnesium measured using a 24-hour recall method in 12,602 men and women (5,678 men and 6,924 women) aged 40-69 years in the UK Biobank Study with complete data for all body composition and dietary measurements. For grip strength the maximum of both hand measurements was used. Total FFM was expressed either as the percentage of body weight ((FFM kg/body weight kg)*100) or the fat free mass index (FFMI – fat free mass in kg/height2). Dietary intake was divided into quintiles and regression analysis (analysis of covariance) was used to calculate the associations between the measures of body composition and grip strength and adjusted for the covariates of age, smoking status, physical activity, energy intake, dietary mis-reporting, and menopausal status and HRT medication in women. FFMI was also adjusted for total fat mass and grip strength for standing height. Analysis was performed in STATA SE 14.0.
Results
Mean age in men was 56.7 Y in men and 55.4 Y in women. Whole body mean FFM% was 76.1% and 65.3% and mean FFMI was 20.3 kg/m2 and 16.5 kg/m2 in men and women, respectively. FFM% was significantly and negatively associated with percentage protein intake (-0.33% per quintile (P trend <0.001) in men and -0.28% (P<0.001) in women) whereas for magnesium intake the association was positive (0.42% per quintile (P trend <0.001) in men and 0.45% per quintile in women (P<0.001)), in the fully adjusted models. With both nutrients together in the statistical models the association with protein was more negative and that of magnesium was more positive in men (protein -0.36% (P<0.001), magnesium 0.46% (P<0.001) and protein -0.32% (P<0.001), magnesium 0.50% (P<0.001) in women, indicating an interaction between the nutrients. There was no association between FFMI or grip strength and either dietary protein or magnesium in either men or women.
Conclusion
We found strong positive associations between magnesium intake and FFM% and a negative association with protein. The finding of the direction of the association with protein was surprising, although given the inconsistent results from previous cross-sectional and interventional studies may not be entirely unexpected. However, the associations were strengthened when both nutrients were included in the statistical model, suggesting an interaction and supporting our previous findings for magnesium that were previously found only in a female population (3). We also found no association between grip strength and either nutrient also supporting our previous findings (3). These results suggest the interaction between protein and magnesium intake on skeletal muscle mass and function deserves further research.
References: (1) Murton AJ, Proc Nut Soc, 74, 387-396 (2) Hickson M, Proc Nut Soc, 74, 378-386 (3) Welch AA et al, JBMR, 2015 Aug 19. doi: 10.1002/jbmr.2692.
This research has been conducted using the UK Biobank Resource